1. Field of the Invention
This invention pertains to electrical safety devices, and more particularly to apparatus which facilitates positioning electrical safety devices at desired locations on mobile storage systems.
2. Description of the Prior Art
Horizontally movable systems for storing books and other materials are well known. The mobile storage units may be moved along a building floor under either manual or electrical power. It is conceivable that a person may operate a mobile unit without realizing another person is standing in the aisle next to the unit. That situation is especially dangerous with electrically powered mobile units. To reduce the danger to a person caught next to a moving unit, various safety devices are commonly employed. A particularly desirable safety device is an elongated pressure operated safety switch attached horizontally along the external edge of a shelf. Momentary contact of the safety switch breaks the circuit controlling the mobile unit motors to stop movement of the unit.
A problem with present safety switch designs is the exposure of the electrical wires leading to the switches, thus creating the risk of damage to the wires. A related problem is that, in providing a neat appearance as well as minimizing the amount of exposed wire, the wire lengths are usually cut to accommodate only one shelf location within the unit frame. As a result, the shelf with the safety switch cannot be readily repositioned on the frame without altering the wires. Depending on the desired new location of the shelf relative to the original location, a way must be found to either pull additional wire from somewhere in the circuit, or to protect and hide newly created excess wire; both procedures are time consuming and inconvenient.
Thus, a need exists for apparatus which facilitates vertical adjustment of mobile storage unit shelves having a safety switch attached thereto while maintaining wire protection and a neat appearance.